Seems sound goes away when you fire the howitzer alot. Playing on a 20 man server and after firing around 15 rounds of explosive the whistling didnt go away but the other sounds glitched and you couldn't hear most of them.

Not really a bug, but I tested with the scope and yo can't hit the targets under my crosshair in the below screenshot because of the crater edge, it would be nice to be able to shoot out without having to stand up